US3432145A

US3432145A - Mobile crane

Info

Publication number: US3432145A
Application number: US606867A
Authority: US
Inventors: Clarence T Mudge
Original assignee: SUNSET FUEL CO
Current assignee: SUNSET FUEL CO
Priority date: 1967-01-03
Filing date: 1967-01-03
Publication date: 1969-03-11
Anticipated expiration: 1986-03-11

Description

March 11. 1969 IOBILE CRANE med Jan. :5. 1967 11- r 26. rice I M udge "WEN-roe Hffys.

United States Patent 8 Claims ABSTRACT OF THE DISCLOSURE A mobile crane adapted to be mounted on a vehicle body, trailer, dolly or otherwise suitably supported, comprising an upright support mast, a boom assembly mounted on the mast, load-attaching means depending from the boom assembly, and load-lifting apparatus mounted within a protective housing secured to the post. The load-lifting apparatus includes a rotatable drum connected by means of a cable to the load-attaching means, a motor mounted above the drum for driving the same oriented with the axis of its shaft and disposed horizontally, and a speed reduction unit interposed between the motor and drum providing a driving connection between the two.

This invention relates to load-handling apparatus, and more particularly, to such apparatus which takes the form of a power-operated crane that may be mounted on the body of a vehicle, trailer, dolly or otherwise.

A common form of crane of the type indicated comprises an upright mast for mounting on a vehicle, a boom assembly mounted on the mast, a cable-operated, vertically-shiftable load-attaching device depending from the boom, and power-operated mechanism for taking up and paying out a cable which connects with the load-attaching device. The usual power-operated mechanism employed includes a rotatable drum upon which the cable is Wound, and an electric motor mounted below the drum and operable to drive the same.

A crane of the type described may be mounted on a vehicle, such as a truck, which operates and remains out of doors a good part of the time. Thus, the crane is often exposed to, and is expected to withstand, harsh weather conditions. Known devices, however, after extended periods of such exposure, have frequently experienced motor failure causing the device to become inoperative, and requiring time-coming and expensive repairs. Such failure has often resulted from water, due to rain or snow, getting into and damaging the motor.

There are a number of reasons why such damage has occurred with known cranes..For example, many cranes have no protective covers at all for their motors, and in such cases, water easily enters the motors through the usual ventilation openings provided in the motor housings. However, even on cranes where suitable protective covers are provided, water damage is still a problem. This results from the fact that water flows along the cable connected with the take-up drum and collects on the drum. Water on the drum then drips onto the motor which, as indicated above, is usually mounted directly below the drum. This latter-mentioned problem is compounded where, as in many cases the motor is oriented with its shaft disposed upright and a set of ventilating openings facing directly upwardly.

A general object of the present invention, therefore, is to provide a novel crane which avoids the above-indicated difficulties encountered with known cranes.

More particularly, an object of the invention is to provide sue-ha crane which employs an electric motor, and which includes novel means supporting the motor and protecting the same against water damage. Thus, the in- 3,432,145 Patented Mar. 11, 1969 vention provides novel housing structure which forms an effective shield for the motor, shielding the same from moisture outside the structure. The housing structure accommodates mounting of the motor with the drive shaft thereof disposed horizontally whereby the likelihood of any moisture entering the ventilation openings of the motor is negligible.

Another object is to provide a crane of the type described which further includes a rotatable drum driven by the motor, and a cable extending between the drum and a load-attaching means for the crane, wherein the housing structure accommodates mounting therein of the drum with such located below the motor whereby any water which flows along the cable and collects on the drum cannot drip onto the motor.

The crane contemplated herein comprises an upright mast upon which the housing structure is mounted. A further object of the invention is to provide, in such an organization, housing structure of the type so far described which includes portions thereof that function as a brace for the mast.

These and other objects and advantages attained by the invention will become more fully apparent as the description which follows is read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevation of a crane as contemplated herein mounted on the rear portion of a pickup truck, with portions of housing structure forming part of the crane broken away to illustrate load-lifting means also forming part of the crane; and

FIG. 2 is a view taken along the line 2-2 in FIG. 1, also with portions of the housing structure broken away.

While a crane constructed according to the invention is described herein in connection with mounting on a vehicle, it should be understood that such is for the purpose of illustration only, and that the crane may readily be supported on other suitable means.

Turning now to the drawings, and with reference first to FIG. 1, shown generally at 10 is the rear portion of a vehicle such as a pick-up truck having the usual truck body 12 including a floor 12a, and rear wheels 14, supporting the body for travel over the ground.

Mounted on floor 12a, and indicated generally at 16, is a crane, or load-handling apparatus, as contemplated herein. The crane comprises an upright mast 18 having a pair of hollow cylindrical mast sections including a lower mast section 18a, the upper end of which is nested within an upper mast section 18b. Upper section 18b is adapted to rotate about lower section 18a, and is supported on the lower mast section through a suitable thrust bearing 20 (shown in dashed outline) which is appropriately mounted within the interior of section 18b and which seats on the top of mast section 18a. Further accommodating relative rotation of the two mast sections is a roller bearing assembly (not illustrated) which provides rolling contact between the outside of section 18a and the inside of section 1811, and which is mounted within a collar 22 secured adjacent the base of section 18b.

A suitable friction brake 23 is mounted on mast section 18b and is operable releasably to clamp the two mast sections together, thus to prevent relative rotation between the sections.

The lower end of mast section extends downwardly through suitable bores provided in a pair of substantially flat, horizontally disposed

mounting plates

24, 26 and through a similar bore provided in floor 12a.

Mounting plates

24, 26 are fastened against upper and lower sides, respectively, of the floor by means of fasteners, such as fasteners 28, and mast section 18a is welded to upper mounting plate 24. A gusset 29 is provided which is welded both to the lower mast section and to plate 24.

Supporting the portion of mast section 18a which extends downwardly through plate 26 is a hollow cylindrical sleeve 30 which freely receives the mast section and which is welded to plate 26. Elongated support struts, such as struts 32, are provided having one set of ends welded to the outside of the sleeve and the other set of ends welded to plate 26. These struts provide support for the sleeve.

The crane further comprises an extensible boom assembly including an elongated, hollow, cylindrical section 34, and an elongated, cylindrical, extensible arms 36. Section 34, adjacent one end thereof, is provided with a diametrical bore 34a, and arm 36 is provided with plural diametrical bores 36a spaced along the length of the arm. Section 34 and arm 36 are releasably locked together by means of a key 38 which extends through bore 34a and an aligned bore 36a of the arm. The other end of section 34 is pivotally mounted on mast section 181) by means of pivot mounting 40. Suitably mounted on the outer end of arm 36 is a pulley assembly 42 including a pulley wheel 42a.

Also forming part of the crane is an adjustable chain device 44 for adjusting the inclination of the boom relative to the mast. This device includes an elongated clevis 46 having one end pivotally connected at 48 to pulley assembly 42, and its other end connected by a pin 50 to one end of an elongated chain 52. The chain, adjacent its other end, releasably engages a notched locking plate 54 secured to one end of an elongated fastener 56. The other end of fastener 56 is pivotally connected at 58 to a pulley assembly 60, including a pulley wheel 60a, secured adjacent the upper end of mast section 18b.

Considering FIGS. 1 and 2 together, shown generally at 62 adjacent the lower portion of mast section 18a is housing structure as contemplated herein, and mounted within this housing structure is load-lifting means 64 for the crane.

The housing structure includes a pair of elongated upright end plates, such as plate 66, welded to the outside of mast section 18a adjacent diametrically opposite sides thereof. Plates 66 are also welded to the top of mounting plate 24. Welded to the outside edges of plates 66, and also to the top of plate 24, are laterally spaced,

upright side members

68, 70 also forming part of the housing structure. A base bar 72 is provided which extends between

side members

68, 70 and which is welded to the top of mounting plate 24.

The housing structure further includes a detachable, somewhat L-shaped cover 74, which, in operative position as shown, spans the side members and forms a top and end wall for the housing structure. The cover is provided with suitable side flanges, such as flange 74a, which, with the cover in place, overlap the side members of the housing. The cover is also provided with louvers 78 which enable ventilation of the equipment mounted within the housing. The cover is held releasably in place by virtue of frictional engagement with collar 22 which engages a margin of the same adjacent the mast, and with base bar 72 which engages a flange 74b formed adjacent the base of the cover. The cover is formed of a suitable resilient material, such as a sheet steel, and when in place as shown is somewhat deformed whereby it is resiliently pressed against collar 22 and bar 72.

Considering now the construction of load-lifting means 64, in general terms it includes a reversible electric motor 80, which may be operable on either AC. or DC. current, a speed reduction unit 82, and a rotatable drum 84. Motor 80 is mounted adjacent the top of the housing, with its shaft disposed horizontally, on a plate 86 which extends between and is welded to

side members

68, 70. The motor is held in place on plate 86 by suitable fasteners, such as those shown at 88. The motor casing is provided, adjacent opposite ends, with ventilation openings, such as openings 80a (FIG. 2).

Speed reduction unit 82 is mounted below the motor by means of fasteners 90 on a plate 92 which, like plate 86, extends between and is welded to

side members

68, 70. The motor and .drive unit are connected together by means of belts, or belt drive means, 94 trained over

pulleys

96, 98 suitably secured to the output shaft of the motor and to the input shaft of unit 82, respectively. Unit 82 and belts 94 are also referred to herein collectively as connecting means.

Drum 84 is journaled for rotation about a substantially horizontal axis in suitable bearings, such as hearing 99 in FlG. 2, (not shown in FIG. 1) mounted on side members 68, 7t). Suitably secured to one end of the drum is a sprocket wheel 100. The drum is connected to speed reduction unit 82 by means of a chain 102 which passes through a suitable opening 92a in plate 92 and which is trained over wheel 1%, and a sprocket wheel 164 secured to the output shaft of unit 82.

A pulley assembly 1%, including a pulley wheel 1060 is provided adjacent the base of the housing structure. This assembly is secured to mast section 18b adjacent an opening, or passage, 168 provided in the side of the mast section. Opening 108 communicates with the interiors of housing 62 and mast section 18b.

Crane 16 further includes a block, or load-attaching means, 110 including a pulley wheel 110a depending from the boom assembly as shown. The block is connected to drum 84 by means of an elongaed cable, or tensioning element, 112. The cable has one end connected at 114 to pulley assembly 52, its other end wound on drum 84, and between its ends is trained over pulleys 110a, 42a, 60a and 166a.

Power is supplied to motor 80 from a suitable source (not shown) through cable 116 which extends through a suitable opening provided in the housing and which connects with the source. A suitable control (not illustrated) is connected to the cable for controlling the flow of such power whereby the motor may be operated in either direction and stopped.

Explaining the protection afforded motor 80 with the construction shown, with cover 74 in place as illustrated, the housing structure provides a protective shield for the motor, shielding it from moisture outside the housing. Further protection results from the fact that the motor is oriented with its drive shaft, and hence its ventilating opeings, disposed horizontally whereby during times that the cover is removed, moisture cannot fall into the motor casing through such openings.

With drum 84 mounted below the motor, and cable 112 ntering the housing through passage 108 which is located at a point also below the motor, no water which may flow along the cable and collect on the drum can drip onto the motor.

Cover 74, which is held in place only due to frictional engagement with collar 22 and bar 72, may readily and quickly be removed for inspection and maintenance of the various apparatus mounted within the housing structure, and the cover is provided with louvers which enable ventilating of such apparatus without permitting rain or snow water to enter the housing. With the motor thus protected, the crane can readily withstand long periods of outside exposure without danger of the motor failing due to water damage.

The end plates and side members forming part of the housing herein, also act as a brace supporting mast section 1817.

While an embodiment of the invention has been described herein in connection with a particular type of crane, it is appreciated that the invention may be used as well with other types of load-handling apparatus. It is appreciated also that variations and modifications may be made in the invention without departing from the spirit thereof.

It is claimed and desired to secure By Letters Patent: 1. In load-handling appartus in operative position including an upright mast, a boom assembly mounted on said mast, and load-attaching means operatively connected to said boom assembly,

housing structure including a pair of spaced-apart lateral side members mounted on said mast, and

load-lifting means located within said housing structure for raising and lowering said load-attaching means and any load attached thereto comprising a rotatable drum located between and journaled on said side members, operatively connected to said load-attaching means, an electric motor mounted on a support means located between said side members above said drum, and

means connecting said motor and said drum producing a driving connection therebetween whereby operation of said motor causes rotation of said drum.

2. The apparatus of claim 1 which further includes an elongated tensioning element operatively interconnecting said drum and said load-attaching means, extending into said housing structure at a point located below said motor.

3. The apparatus of claim 2, wherein said mast includes an elognated hollow mast section having means adjacent the base thereof defining a passage communicating with the interior of the mast section and housing structure atv said point below said motor, and said tensioning element extends along and through said mast section, and into said housing structure through said passage.

4. The apparatus of claim 2, wherein said motor is mounted with its shaft extending substantially horizontally.

5. The apparatus of claim 4, wherein said means connecting said motor and said drum comprises a speed reduction unit mounted on said side members between said motor and said drum, and belt drive means operativel interconnecting said motor and said unit.

6. The apparatus of claim 5, wherein said housing structure further includes upright elongated end plates adjacent an end thereof joining said side members to said mast, and, together with said mast closing off said end of said structure, said end plates and side members acting together as a brace for said mast.

7. The apparatus of claim 5, wherein said housing structure further includes a detachable cover, in operative position detachably mounted on said side members.

8. The apparatus of claim 5, wherein said speed reduction unit is positioned below said motor,

References Cited UNITED STATES PATENTS 1,440,722 1/ 1923 Dunnam 212- 2,804,979 9/1957 Lassiter 212-59 2,923,418 2/1960 McGuire 212-59 2,940,621 6/1960 White 212-59 3,235,229 2/1966 Buschbom 254-186 3,306,467 2/1967 Weempe 212-55 2,531,346 11/1950 Schuchert 187-2 2,565,091 8/1951 Reed 212- 2,974,809 3/1961 Sellars 212-34 3,048,371 8/1962 Klimek 254-187 3,276,546 10/1966 Slais 187-2 EVON C. BLUNK, Primary Examiner. HARVEY C. HORNSBY, Assistant Examiner.

US. Cl. X.R. 212-59